Quick-break knife-switch.



Q. D. PLATT. y QUICK BREAK'KNIFE SWITCH.

APPLICATION FILED MAE. l, 1909.

963964," i Patented July 5, Milf;

W/TNESSES g/NVENTOH CLARENCE D; PLTT, 0F BRIDGEPORT, CONNECTICUT.

QUICK-BREAK KNIFE-SWITCH.

seance;

Specication of Letters Patent.

Patented July 5, 1h10.

l' Application led March l, 1909. Serial No. 480,605.

means for automatically breaking the oir-- cuit in a, quicker and more efiicient manner than can be done with the ordinary 'form 'of knife switches in which the break is de pendent upon movement of the hand only.

, The obj ect in quick break switches is to prevent arcing between the contact parts which if excessive, as is frequently the case with` ordinary switches, will quickly destroy the usefulness of the switch.

The object of the present invention is to provide an improved quick break switch which will .meet all the mechanical andelectrical requirements lof the trade and i the underwriters and which can be manufactured at a minimum cost. Switches of this type as ordinarily constructed require special parts and much fitting, which makes the cost prohibitive 'and prevents their general use, es-

pecially in the smaller sizes.

The present invention is especially adapted to the smaller sizes of switches where a quick break is most to be desired on account of-their being more frequently operated by inexperienced persons havin slight knowledge of their use. My nove switch differs from ordinary switches of this type in the construction of, the blades only, the other parts of the'switch being of ordinary construction, so that the invention enables mo to manufacture all of the parts except the vblades in the ordinary or any preferred manner and then t0 attach either a quick Abreak or a regular bladeas may be preferred, regular and quick break blades being I thus obviate the necessity of a. special construction of switch and greatly reduce the oost of quick break switches. Furthermore, my novel quick break blades may be made from ordinary blaiies, a few simple operations preparing the blades for `the attachment of the auxiliary blades,- the springs, etc.

With these and otherfobjects in view I have devised the novel structure which I will now describe, referring to the accompanying drawing :torminr1r a part .of this specification and using reerence characters to indicate the several parts:

Figure 1 is an elevation of my novel switch in the closed position; Fig.-2 a plan view correspondingwith Fi 1; and Fig. 3 is an elevation illustratingt e operation ofthe switch, the lever beingpartlyk raised Vas when breaking the circuit, the auxiliary blade being still in engagement with the Jaws.

y 10 denotes the base'which may be made of slate, porcelain or any suitable insulating material, and 11 and 12`platesvrigidly secured thereto and each carrying a binding screw 13. A

14 denotes a double standard extending upward from plate 11, and 15a blade the forward end of which is pivoted to' the standard asat 16;' The rearl end of the glade is provided with an insulating han- 18 denotes the jaws which extend upward from plate 12 and have an inward spring action, that is toward each other. One of the jaws is provided with a lug 19 struck inward from the metal thereof which serves as a stop tolimit the downward movement in the circuit closing position.

20 denotes a recess in the under edge of the blade, which receives a portion- 21 of an auxiliary blade which lies in horizontal alinement therewith.

The auxiliary blade has a shank portion 22 below the plane of the lower edge of the blade 15 which is offset laterally so that while the portion 21 normally rests 1n the recess 20' and in alinemcnt with the'ma'mi blade so as to just fit said recess, the auxlliary blade as a whole can be pivotally connected to one side of the main blade, as by a bolt 23. A spring, in the present mstance a spring washer 24 under the head of the bolt, acts to retain the shank of the aumliary blade in close contact, that is in elec trical contact, with the blade.

25 denotes an arm extending from 'the shank and having at its end a head 26 which is adapted to engage the under side of the blade, in the opening movement, and acts as a stop to limit the separation of the blades, as will be more fully explained, and to which one arm of a spring .27 is secured, said sprin being coiled about the bolt and the end' o the other arm being bent inward to engage aI hole- 28 in the blade. This spring acts to normally retain the auxiliary blade closely'in recess 20 in the blade. The closing' movement is to swing the blade downward in the usual manner, forcing the auxiliary blade and the blade between the jaws until the downward movement 'is stopped by the engagement of the auxiliary blade with stop lug 19, as in Fig. 1.

vIn Fig. 3 I have shown the position'of the parts just before the circuit is broken. The blade'lias'beeu raised out of engagement with the jaws but the auxiliary blade is retarded and is still retained between the jaws by the pressure of the jaws thereon. This pressure is sufficient to retain the auxiliary blade between the jaws keeping the circuit -closed until the head of arm 25 engages the under side of the blade. After the engagement of the head with the blade, the se iaration of the jaws is stopped and' continuer upward movement of the blade will lli't the auxiliary blade upward also until the latter is released from the tension of the jaws..

The instant this release takes place, the spring will return the auxiliary blade to its normal position with a snap. This snap oit' the auxiliary blade into engagement with the blade takes place so quickly and the auxiliary blade is so widely separated from the jaws when it does take place that arcing is rendered practically impossible.

It will now be understood that the structure as a whole is simple and of-low cost, requiring no special construction of base or standard and jaws. For instance, supposing the blade 15 were of uniform width, having no recess and no auxiliary blade, the whole would constitute an ordinary blade switch. By simply punching or otherwise forming the recess 2O and a bolt hole and the hole 28, it is ready to have the auxiliary blade and spring washer 24 and spring 27 attached, thus converting it into a quick break switch. Consequently ii the manu facturer has on hand a quantity of ordinary bladeswitches, he can quickly, to lill an order, convert tliein into quick break switches. The i'ccessing of the blade 15 at 9.0 avoids the necessity ot 'making any change in the jaws 18 or stop 19, and the offsetting of the auxiliary blade enables one portion of it to fit that recess while another portion extends along and up against one side of the main blade and is pivoted there eeaoea to so as to bear flat against the main blade to insure good electrical contact. y It will of course be obvious that the spe,- ci'al details of construction are not of the essence of the invention but that these detailsv may be greatly varied! without departing from the principle of the invention.

I claim dit;

1.,A switch ofl the character described comprisin a pivoted main blade having a portion o one ed e cut away to Jforni a recess, an auxiliary. blade and offset to form a body portion adapted to till said recess.ai id a sprin for normally holding said auxiliary b la e in said recess, said auxiliary blade being also provided with under side of said main blade to limit the separation of the blades.

2. A switch of the character described comprising a main blade having a portion et one ed e cut away to form a recess, an aux iliary lade of the same thickness as said inain blade and provided with a, body por` tion adapted to till said recess, said auxiliary blade being pivotally mounted on said main blade and provided with an extension to enn gage the underside of the main blade to linut the separation of the blades, and a spring for normally holding said'auxiliary blade in said recess. v

3. A switch of the character described comprising a main blade having a portion oi one ed e cut away to form a recess, an'aux-- lade of the same thickness as said main blade and provided with a body poriliary tion adapted to lill said recess, a bolt carried by said main blade and pivotally supporting said auxiliary blade, an a spring encircling said bolt and having arms engaging both blades, and contacts adapted to be en a ed by both blades, the said auxiliary bla e ing provided with an extension to engage the underside of the main blade to limit the separation of said blades.

4. A switch Aof the character described comprising a main blade having a portion of one edge cut away to form a recess, an auxiliary blade of same thiclniess as said main blade and pivotally mounted on one side oi' the latter, one end of said auxiliary blade being oii'set to forni, a body adapted to fill said recess, the other end being provided with an extension to forni a stop for iiiniting the separation of said blades, and al spring acting to hold the body oit said auxiliary l.

a ortion norn'iall occu in said recess and having an offset shank portion which is provided with an arni having a head adapted to engage the under side et the lade pivoted to said main Y Zilli) blade in the o'peung movement, said shauk to return the auxiliary blade to its nofmalj..

l: portion overlappm one side of the mam position with a. snep when released.

d t e blade and" pivote reto, a spring acting to In testimony whereof` I ax my signature, normally retain the auxiliary blade in the in presence of two witnesses. l-

5 recess, and spring jawsvacting to retain the CLARENCE D. PLT'.;y

blades in the closin osition, the auxiliary Witnesses: blade being retarde y the jaws until the A. M. Woos'mx,

head engages the blade andthe spring acting y S.' W. A'rxmn'roN. 

